(CNN) -- As the trial for two American journalists began Thursday in North Korea, a former Japanese journalist has recounted his experience while he was imprisoned in the country for about two years.

"When I was first arrested, I thought my life had ended. I was wondering how I would be killed, by public execution, by poisoning?" Takashi Sugishima told CNN in a recent interview.

International press freedom group Reporters Without Borders says the two American journalists, Laura Ling and Euna Lee, are the first foreign journalists since Sugishima to be held for any length of time in North Korea.

While on his fifth visit to North Korea, Sugishima -- an economic researcher and a retired reporter for Japan's Nihon Keizai financial daily, according to the Los Angeles Times -- was seized and imprisoned in December 1999. He had been part of a delegation visiting Pyongyang, according to the Los Angeles Times.

Authorities accused him of spying for Japan and South Korea, charges both nations denied, according to the newspaper.

Sugishima also denies the allegation, and said he never faced trial for the charge.

He said he was fearful while in prison. "They [prison guards] would smile at me, but they could change their attitude the next second without any guilt. I tried to be as friendly as possible, but I never knew when they might decide to kill me," Sugishima said.

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Thinking he would be forced to spy for Pyongyang, he said he tried to hang himself, but an old sink broke his fall, saving him.

Sugishima related his harrowing two years in prison to what Ling and Lee are possibly experiencing.

"They're likely being asked why they were there, what they filmed, what kind of report they're trying to make," he said.

Sugishima was released in February 2002.

Authorities told him it was because of pleading from Japan and his family, but at least one North Korea analyst, Shigemura Toshimitsu, said Sugishima was used as a bargaining chip to influence relations with Japan.

He said he believes Pyongyang is using the same tactic with Ling and Lee to try and negotiate with Washington.

Ling and Lee are reporters for California-based Current TV, the media venture of former U.S. Vice President Al Gore.

The two were reporting on the plight of North Korean defectors living along the China-North Korea border when they were taken into custody March 17.

Their trial began Thursday, according to U.S. State Department spokesman Ian Kelly, who cited media reports. He said the department was informed by the Swedish ambassador to North Korea that no observers are allowed in the courtroom.

Analysts have said the trial could be short. The women could face years in labor camps if convicted.

North Korea said the reporters had entered the country illegally. The women were accused of "hostile acts" and charged with spying.

Contact with the women has been limited.

The Swedish ambassador to North Korea was allowed to see the two journalists Monday, according to the U.S. State Department. Sweden represents the United States in North Korea because the two countries, which fought on opposite sides during the three-year Korean war in the 1950s, do not have diplomatic relations. The ambassador also met separately with the two journalists March 30 and May 15.

Despite the limited communication, the families say they've heard enough to know the women are "terrified" and "extremely scared."

"While I am trying to remain hopeful, each day becomes harder and harder to bear," Ling wrote in the letter that her husband, Iain Clayton, read on "Larry King Live." "I am so lonely and scared."

Ling's sister, CNN special correspondent Lisa Ling, made a direct on-air appeal to North Korea in an effort to win the release of her sister and Lee.

"We don't know the details of what happened on March 17th, but if at any point the girls went into North Korea, then we apologize on their behalf," Ling said. "They never intended to do so."